The wells of a plate with antibodies or antigens are covered. 2. The samples are added, controls and standards to wells of the plate and are incubated to temperatures that oscillate between room temperature and 37 C, by a period of time determined, according to characteristics of test. During the incubation, a part of the antigen of the sample is united to the antibody of the covering of the plate, or the antibody of the sample is united with the antigen located in the covering of the plate, based on its presence and amount in the analyzed sample. 3.

After the incubation, antigen the united organizations or antibodies are not washed and they retire of the plate, using the ELISA washer that uses a suitable one. 4. Next, a secondary antibody, denominated adds itself which has an enzyme that will react with a substrate to produce a change of color. 5. A second period of incubation begins then, during which the conjugated one will be united to the complex antigen-antibody in wells of the plate. 6. After the incubation, a new washing is realised to retire of wells of the plate any vestige of the not united conjugated one. 7.

A substrate is added. The enzyme will react with the substrate and will cause to a change of color in the solution, offering means to measure conjugated amount of that simultaneously will say how much complex antigen antibody is present. Another period of incubation will allow that this reaction takes place. 8. Turned the time of incubation, a reagent is added to stop the reaction substrate-enzyme and to prevent additional changes with color. Generally this reagent is a diluted acid. 9. Finally, the reading of the plate in the ELISA analyzer takes place. The values of the results are used to determine the amounts of present specific antigen or antibody in the sample.